Emissions - the straight dope.

[GuyFawkes]

suck, squeeze, bang, blow.

basically wherever you are in the western world there two types of emissions and two classes of emissions, that sooner or later you will run in to.

The two classes are 1/ particulate and 2/ gaseous

The two types are 1/ hydrocarbons and 2/ oxides of nitrogen.

Diesels are cool, because they are not stoichiometric engines like a carburretor fed petrol / gasoline motor, fuel is METERED, and can be metered down to zero, so diesels can run as lean as you like, they just produce less power.

Stoichiometric or Theoretical Combustion is the ideal combustion process during which a fuel is burned completely. A complete combustion is a process which burns all the carbon (C) to (CO2), all hydrogen (H) to (H2O) and all sulfur (S) to (SO2). If there are unburned components in the exhaust gas such as C, H2, CO the combustion process is uncompleted.

That and things like Harry Ricardos pre combustion chamber and a listers low piston speeds and so on and so forth mean you can do a good job on the hydrocarbons and particulates inside the combustion chamber, and what you don't catch there you can effectively filter out and trap or convert in the exhaust system.

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OXIDES OF NITROGEN ARE A BITCH.

Air is 79% N2 or nitrogen gas, so every time every engine on the planet sucks, it is drawing in 79% nitrogen.

Every time every engine on the planet bangs, that heat of combustion makes that nitrogen combine with that other element that is very common in air, Oxygen or O2 gas, to form nitrogen oxides.

If you raise combustion temperatures you raise nitrogen oxides production (that lister CS head is looking better and better innit)

If you lower combustion temperatures you lower nitrogen oxides production, but may increase hydrocarbon production, and you can only go so low and your engine misfires and stalls.

So, you can either reduce the amount of nitrogen the engine is drawing in, which will consime more power than the engine produces and cost ancillary equipment 100 times the value of the engine, and the weight

OR

You can reduce the amount of oxygen, so there is only just enough to burn the fuel, and no excess to burn the nitrogen.

in a chaotic thing like a combustion chamber you can only approach this, you will NEVER EVER EVER get anywhere near zero oxygen left to burn nitrogen while all fuel is burnt.

how do you "dilute" air intake to the engine to reduce the excess oxygen?

easy

feed the exhaust gas back into the engine, after intercooling it, and of course you have to meter it, an engine on open rack needs more oxygen than an engine on a closed rack, and of course you have to filter the nitrogen oxides out of the exhaust gas as much as you can.

NONE OF THIS CAN BE DONE INSIDE THE ENGINE OR HEAD

it takes complex, expensive, voluminous and power sapping ancilliaries, but, it can be done.

the original lister cs, you will find, is ahead of the curve on this, variable compression and ricardo indirect injection help, a lot.

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so, you will see from the above, even a hydrogen burning motor wil no liquid lubricants going anywhere near the combustion chamber will not be zero emissions, it will still produce very large amounts (hydrogen burns hot) of nitrogen oxides, UNLESS you feed it pure O2 from a bottle.

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european style low sulphur diesels will help with the hydrocarbons and particulates, a LOT

I don't know anything about the various alternative bio fuels, I suspect some will be winnders and some losers

NONE OF THEM WILL HELP WITH NITROGEN OXIDES

FAILING ANY PART OF AN EMISSIONS TEST IS STILL A FAIL

Catalytic converters will address these problems, but they also present roundabouts and swings, they work best on the nitrogen oxides when the engine is running rich, and they work best on carbon oxides and hydrocarbons when the engine is running lean.

The final answers will be a mix of exhaust gas regeneration (re introduction to the motor) and multi stage catalytics, multi stage is not multi way as is 2 or 3 way cars. first stage will probably be electrci spark driven plasma chamber, send stage traditional catalyst.

the final answers will be expensive, especially for a 400 buck motor, and sap power.

for more reading see http://w4.siemens.de/FuI/en/archiv/zeitschrift/heft2_98/artikel08/

[mobile_bob]

Guy:

your input on the subject is much appreciated,


the thing that pisses me off, is the fact that if you shut down every lister, listeroid, petter, changfa, etc and took an emmission reading on a planetary scale, then restarted every friggin one of them, i would bet a dollar to a dog turd you could not find an instrument known to man that could register any increase in particulate, co, co2, nitrous oxides or anyother detrimental component.

i suppose it is possible that in some remote village that has a few hundred of these things running you might see a slight increase locally, but those villages are not regulated by the EPA.

no one will ever convince me that these engines as they are being used in the US are contributing anything measureable to the pollution problem.

they have just been caught in a broad sweeping net, and it is a shame.

i suppose if you had a several thousand of them running 24/7 in the US there might be an issue in places like california, but then again california has issues anyway.

besides it would take a couple hundred years to get enough awareness of these engines, produce, ship and impliment them to get to any serious scale.

i also wonder how much nitrous oxides are produced by a listeroid when the combustion temps are so low, unless you are running the engine at near its rated capacity, it would appear most folks arent running at capacity most of the time anyway.

evidence of low combustion temps comes from reports of those that balance the twins based on exhaust temps that are around 500 degrees F. ,  this tells me that the engine is not anywhere near its rated load capacity or it would be upward of 1100 degrees as is the norm for larger commercial diesels at load.

i personally am waiting to see if someone can do some serious testing on these engines, for particulate and nitrous oxides at no load, part load and full load. perhaps running at part load or derating these engines can bring them in to compliance. seems plausible.

bob g

[GuyFawkes]

In theory efficiency in an engine = low exhaust temp, runing slow is efficient, so you should have lower temps.

as to the rest, London stinks, literally, I don't like going there, london has so much traffic it affects the atmosphere and the health of the people, but they make the laws, and they are the centre of the universe, sure washington is the same.

out in the country, nobody has a problem with emissions, but you must remember the golden rule

[GuyFawkes]

I should also point out, apart from the capital cities that make the laws being the whole, not merely the centre, of the universe so their problems such as air pollution are the only ones that exist, the following.

a lister engine (for example, any IC engine will do) with the fuel system and injector removed, spun by an electric motor, eg driven and not driving, with a cherry hot ceramic plate in the head will produce significant quantities of nitrogen oxides and will consequently fail an stringent emissions test, even though it is not burning any fuel of any kind or producing any power of any kind.

think it through and you will see that if you want to make a motor that produces as much nitrogen oxides as possible, you need a motor that burns a LOT of fuel, draws in a LOT of air, and has high combustion temperatures.

Gentlemen, I give you the jet turbine

If a 747 has a fuel capacity of 57,000 gallons, and the nature of the engine means it produces twice as much nitrogen oxides as a lister, then we have 114,000 gallons of fuel in a lister, and at a peak half a gallon an hour for a 6/1 that is 228,000 hours, the 747 will burn its fuel load in between eight to twelve hours, so we will be generous and double the high number to 24 hours.

10,000 6/1 listers running 24/7 will produce less nitrogen oxides than ONE 747 on one fuel load.

In reality because jets need to stay in the air to make money you are probably looking at 25,000 lister 6/1 for every 747

1400 747s have been built and delivered, so that's equivalent to 35,000,000, yup, thirty five million lister 6/1s

this is JUST 747s

35 million listers with 3 kw heads running 24/7 = 100 GigaWatts of electricity, this is about ONE SEVENTH of the USA installed generating capacity in 1998 (state of virginia has about 6.7 giga watt see http://www.energy.vt.edu/vept/electric/table_capacity_print.asp)

Food for thought, you get to suffer because a few cities are choking on their own emissions and idiots who do not understand even the basics of chemistry or egineering decide to pass laws banning nitrogen oxides emissions.

[mobile_bob]

it just boggles the mind don't it?

when you run the numbers, it becomes apparent to me that the lister/listeroids, petter/petteroids, changfa's etc
arent a pimple on a pimple on the ass of the problem.

bob g

[Halfnuts]

It does, but the pigs are in the farmhouse, they're walking on their hind legs and wearing clothes and looking more like the farmer all the time. 

Halfnuts

[kpgv]

Hi All,
This is an article about the EPA thing, and "Briggs & Stratton".
It's not about Diesels, but still a related issue:

http://denverpost.com/nationworld/ci_3742750

There is apparently a Senator from Missouri (Christopher Bond) that is trying to fight this stuff...


Kevin

[hotater]

Emmisions testers should be sent to any of the currently erupting volcanoes with all their testing gear strapped to their backs and shown that NO MATTER WHAT THEY DO...it *really* doesn't matter in the long run.

To say we're the cause of what happens to the Earth is like blaming ants for changing a cruise ship.  The bio-mass to geo-mass is about the same.

[Doug]

When you consider a billion or people are buying or using these types of engines around the world at som point we have to consider the effect on the life. Even China is begiing to impliment emisions on there ownengines

[SHIPCHIEF]

Yes; I wonder when the EPA is going to fine the State of Washington for the emissions comming out of Mt St Helens? After all, it is 60% of the State's sulfer dioxide output, and it belongs to the State? or is it in the Giford Pinchot National Forest?
Scott E

[akghound]

Are there ANY other countries on the face of this earth that have outlawed these engines?
Ken Gardner

[phaedrus]

Guy’s obviously more or less correct. The detail about airborne turbines may possibly be somewhat off, though. Most of the air that goes through a jet is never combusted. It is “bypass air” used to lower the turbine inlet gas temperature.  I would point out that water vapor in the induction air is used to lower N0x formation in some stationary siemens-westinghouse gas turbine-generators that I’ve installed. There seem to be two mechanisms at work in that process – one is that the latent heat of transformation, the phase change from water droplets to steam, holds the temperature down, thus preventing some N0x formation and perhaps reforming some (I’m not sure about that), and also the steam formed makes it statistically less probable that N2 and O2 will encounter one another. (With weight penalty an airborne turbine might be configured similarly. Whether or not this is desirable is, obviously, a political matter.)

This later mechanism would seem to function similarly to EGR.

For stationary diesels the process ought to work as well, maybe better, as TGs don’t get particularly hot – the blades can’t hold up to the burn, and, as I said, by-pass air is used to dilute and thus cool the gasses coming out of the combustor cans prior to their trip through the “buckets”.

Because the formation of N0x is endothermic see: http://en.wikipedia.org/wiki/Nitrogen_oxide  it would seem to represent a loss of efficiency. The phase change and heating of H2O as steam, while lowering theoretical thermodynamic efficiency, offsets the N0x losses – and may be roughly “a wash”. This is to say that it may be that lowering N0x emissions is or at least can sometimes be consonant with improved overall efficiency in fact.

I wonder if EPA would accept a L’oid that had water induction…  ‘course it would have to be managed by a controller with feedback loop, etc.